The Elizabeth Mine is an abandoned copper mine located on Mine Road in the Village of South Strafford within the Town of Strafford, Orange County, Vermont. The Elizabeth Mine site is situated in a rural setting, on the east side of Copperas Hill. Topography of the area consists of north-south trending hills and valleys. Woodlands surround the mine property. Undeveloped and residential properties border the site's western margin. Site elevations range from approximately 1,000 feet to 1,300 feet above mean sea level. The property consists of two mine tailings piles, one area of waste rock and heap leach piles, two open-cut mines, several adits (horizontal mine entrances), underground shafts and tunnels, ventilation shafts, and several former ore processing buildings. Other on-site structures include those previously used for office space, a shop, a solvent/oil storage shed, an air compressor building, and a garage. The majority of the buildings are in a dilapidated condition. However, one of the buildings and a trailer on the property are rented for residential purposes, and the garage is used to store equipment.

Deposits at the Elizabeth Mine were discovered in 1793. The mine operated from the early 1800s until its closure in 1958. The ore was initially valued for its iron content, and then its pyrrhotite content from which copperas (iron sulfate) was produced. Circa 1830, the deposit was primarily exploited for its copper content based upon the recognition that a significant amount of chalcopyrite (copper iron sulfide) was disseminated in the pyrrhotite. For nearly a century, intermittent production came from the open-cut mine as underground work did not begin until 1886. During the early mining operations, several copper smelters were built on the property. Between 1830 and 1930 approximately 250,000 tons of ore were mined from which approximately 10,500,000 pounds of copper were produced. From 1943 to 1958, 2,967,000 tons of ore were mined producing more than 90,000,000 pounds of copper. All mining operations ceased in February 1958. At the close of the mining operation, the mine property encompassed approximately 1,400 acres.

Past operations at the property consisted of mining, copper smelting, and ore processing. As a result, three mine tailings piles and two open-cut mines were generated on site. The processed tailings in Tailings Pile No. 1 were generated between 1943 and 1958, during the latter period of the mining operation. Ore was ground for flotation through an on-site mill. As copper and pyrrhotite were chemically separated from the ore, tailings sank to the bottom of a flotation separator and were removed. Tailings were dammed to form an impoundment and then were carried via open troughs to a tailings pond for sedimentation. As the valley filled with tailings, the pile's north face rose approximately 100 feet above the natural streambed of Copperas Brook. Tailings Pile No.1 is a flat-topped pile (plateau-like feature) on the lower portion of the property, and covers approximately 30 acres. This pile is comprised of a fine-grained material, uniformly reddish-brown in color at the surface and is the largest accumulation of tailings on site.

Tailings Pile No. 2 overlies Tailings Pile No. 1 at the southwest end of the massive pile. Like Tailings Pile No. 1, Tailings Pile No. 2 forms a raised plateau and covers approximately five acres. This pile rises approximately 30 feet above the surface of Tailings Pile No. 1. The north slope is bare and eroded. An erosion gully is present on the east side of Tailings Pile No.2 where a once buried conduit system has been undermined, exposed, and destroyed. Tailings in Pile No. 2 were also generated during the 1900s and deposited similarly to those in Tailings Pile No. 1. Tailings Pile No. 3 is actually an area of waste rock and heap leach pileslocated farther southwest and upslope of Tailings Pile No. 2. This pile is immediately east of one of the two open-cut mines, and covers approximately 6 acres. Tailings Pile No. 3 is comprised of multiple piles of red and yellow-colored coarse-textured material and slag. Waste in these piles was generated from mining and copper smelting operations during the 1800s and early 1900s. Six copper smelters were built on the property between 1830 and 1916. Slag was observed in Tailings Pile No. 3; some pieces exhibited an iridescent surface.

When mining operations were abandoned, many of the underground areas flooded with ground water. An air shaft, once tunneled to provide ventilation for the underground work areas, currently discharges acid mine drainage to the ground surface. Drainage from this shaft flows overland and empties into an unnamed brook, which discharges to the West Branch Ompompanoosuc River.

The tailings on the property are rich in metals and sulfides. As water passes over and through the tailings, sulfuric acid is produced and the metals within the tailings are dissolved and mobilized. This results in acid mine drainage. Acid mine drainage contributes an elevated load of metals to Copperas Brook and the West Branch Ompompanoosuc River.

The Elizabeth Mine has been previously investigated by State and Federal agencies, and private companies. As part of the various studies, one or more samples of mine tailings, surface water, sediment, fish tissues, ground water, and drinking water have been collected and analyzed for metals. The results indicated the presence of metals that exceeded background levels. The entire length of Copperas Brook and several miles of the West Branch of the Ompompanoosuc River fail to meet Vermont Water Quality Standards based on both numerical and biological criteria.In 2003, EPA determined that the tailing dam at Tailing Pile 1 was unstable and threaten downstream residents and the West Branch of the Ompompanoosuc River. In 2006, EPA finalized the remedial investigation and feasibility study (RI/FS). The RI/FS identified the three major waste areas, TP-1, TP-2, and TP-2, as the major source of contamination and acid rock drainage at the Site. The source areas are the subject of the ongoing Non-Time-Critical Removal Action. The Human Health Risk Assessment identified potential human health threat from contact with the lead contaminated soil at the location of the former Copperas Factories. The groundwater beneath and adjacent to TP-1, TP-2, and TP-3 exceeds federal and state standards and is unsuitable for human consumption. In addition, the water in the underground workings also presents a potential threat to someone who may ingest the water contained within the mine tunnels. The Baseline Ecological Risk Assessment confirmed the findings of previous studies. The entire length of Copperas Brook and the first section of the West Branch of the Ompompanoosuc River downstream from Copperas Brook (known as the WBOR Mixing Zone) has severe ecological impacts. The fish community recovers within a mile below Copperas Brook. However, full recovery of the West Branch of the Ompompanoosuc, as measured by the benthic macroinvertebrate community, does not occur until Union Village Dam, a distance of about four miles. A tributary to Lord Brook that drains the South Open Cut, TP-4, and South Mine areas is also highly contaminated. The discharge from this tributary causes ecological impairment in Lord Brook. The length of the impairment in Lord Brook is believed to be about 1 mile.

EPA selected a non-time-critical removal action (NTCRA) to implement an early cleanup for a portion of the site, at the same time as the remedial investigation and feasibility study (RI/FS). A fact sheet was released in March 2002 presenting an early cleanup action for public comment. The comment period ended April 10, 2002. EPA signed an Action Memorandum on September 3, 2002. In 2003, in response to the instability of the Tailing Dam, EPA initiated an Time-Critical Removal Action. The Time-Critical Removal Action was completed in fall 2005 and successfully stabilized the Tailing Dam and improved the drainage of surface water. The design for the NTCRA was completed in 2009. A value engineering study and independent technical review were completed in 2008. Construction of the remaining NTCRA activities will begin in 2009 and be completed in 2012 or 2013. EPA is implementing the NTCRA is two phases. The first phase began in 2006 and was completed in 2010. This phase included the installation of the shallow groundwater and surface water diversion system, the removal of tailing along Copperas Brook below TP-1, and the installation of a temporary water treatment system to treat discharge during construction activities. The second phase was designed from 2006 - 2009. The second phase includes the relocation of the waste rock at TP-1; containment of the waste rock and tailing within TP-1 and TP-2 in a low permeability cover system; installation of a groundwater interceptor trench; and installation of sediment basins for control of erosion. The design for the second phase of the NTCRA was completed in April 2009. Cleanup work began in June 2009. During 2009, EPA relocated over 130,000 cubic yards of mine waste to an on-site location that will allow the material to be covered to minimize the generation of acid rock drainage. A groundwater interceptor trench was also installed to limit the flow of water into the tailing impoundment. NTCRA work continued in 2010 with the complete removal of TP-3 and the grading of TP-1 in preparation for the cover system. In 2011, the cover system for 22 acres of the 45 acre tailing impoundment was completed. The installation of the cover system was completed in 2012. EPA performing punch list repairs and wetland restoration during 2013 and 2014. This work will continue in 2015. The interim treatment system will also continue to operate through 2016. EPA is planning to construct a passive treatment system to treat the leachate from TP-1 during 2016.

The third and final cleanup action for the Site will be the Remedial Action. A Proposed Plan for the Remedial Action was released in June 2006 with a comment period was completed in August 2006. EPA signed a Record of Decision in September 2006. The design for the Copperas Factory cleanup component of the Remedial Action, called the Phase 1 Remedial Action, was completed in 2008. The cleanup of the Copperas Factories began in June 2009. Initial work at the Copperas Factories included further documentation of the historic resources. By November 2009, all of the lead contamination was covered. The Copperas Factories cleanup was completed in September 2010. The design for the cleanup of the South Mine and South Open Cut component of the remedial action, called the Phase 2 Remedial Action, was completed in 2014. EPA is in the planning stages to begin the cleanup of the South Mine and South Open Cut some time in the next few years. EPA continues to work on the remedial design for the groundwater contamination in the underground workings, called the Phase 3 Remedial Action. The design for the Phase 3 Remedial Action is expected to continue through 2015 into 2016.

EPA has selected a non-time-critical removal action as an initial action to control the release of acid mine drainage from the two large tailing piles (TP-1 and TP-2) and the waste rock/heap leach piles (TP-3).

Entire Site

The next step at the site will be to perform studies to investigate the nature and extent of contamination.A cleanup decision for the entire site was finalized in September 2006.

Time Critical Response

In March 2003, EPA initiated a time-critical removal action to address the instability of the tailing dam. EPA repaired internal dam erosion along the toe of the tailing dam in April/May 2003 and installed a drainage pipe to carry the flow with the 200 acre watershed that was previously flowing through a decaying pipe within the tailing pile. In 2004, EPA installed a soil buttressto stabilize the tailing dam and greatly reduce the chance of a tailing dam failure.The Time-Critical Removal Action was completed in fall 2005.

Non-Time-Critical Removal Action

EPA is implementing the Non-Time-Critical Removal Action in two phases. Phase 1 involved the completion of the stabilization of the Tailing Dam and the installation of a surface water and groundwater diversion system. Several of the Phase 1 activities were completed in 2006 and 2007. The remaining Phase 1 activities are expected to be completed in 2008 or 2009. Phase 2 will involve the cover system for TP-1, TP-2, the removal of the waste material at TP-3, and the treatment of the seeps discharging from TP-1. The draft final design for the Phase II activities was completed in fall 2007. A value engineering study and independent technical review were completed in 2008. The final design was completed in 2009. Additional NTCRA site control measures to control the release of iron rich leachate were completed in 2008. The NTCRA cover system was completed in 2012. The entire NTCRA is expected to be completed in 2015/2016 when the site restoration activities are completed and the passive treatment system is installed and operational.

Record of Decision

EPA signed a Record of Decision in September 2006. The ROD includes the placement of a soil cover over the lead contaminated soil in the Copperas Factories, the closure of the three source areas in the Lord Brook Watershed, long-term monitoring of groundwater, surface water, and sediments and land use restrictions. The Copperas Factory component of the cleanup, called the Phase 1 Remedial Action, was initiated first due to the presence of lead contaminated soil. The Copperas Factory design was completed in 2008. The Copperas Factory cleanup began in June 2009 and the cleanup work was completed in September 2010. An Explanation of Significant Differences (ESD) to the ROD as signed in 2008. The ESD clarifies the handling of the lead contaminated soil at the Copperas Factories and allows for placement of the soil under the NTCRA cap. The design for the South Mine and South Open Cut component of the remedial action, called the Phase 2 Remedial Action, was completed in 2014. The design for the contaminated groundwater in the underground workings, called the Phase 3 Remedial Action, is ongoing and is expected to continue through 2015.

Five Year Review

EPA completed the first Five-Year Review for the Elizabeth Mine Superfund Site in 2014.

Environmental studies over the past year have provided a better understanding of the surface water impacts at the site. The EPA investigations and related reports have documented the substantial ecological impacts caused by the Site. The completion of the soil buttress and drainage improvements in 2005 have prevented the catastrophic failure of the Tailing Dam. In addition, 30,00 cubic yards of tailing were removed from the toe of TP-1 which will further reduce the contaminant loading on the West Branch of the Ompompanoosuc River. The initiation of the NTCRA construction activities in began in 2006 as the next phase of environmental progress. The west side of the Tailing Dam was stabilized in 2006 and the surface water and groundwater diversion system for TP-1 and TP-2 was 90% complete as of December 2007. EPA completed the RI/FS in 2006 and signed a Record of Decision in September 2006. The design for the Phase II NTCRA components began in 2005 and was completed in 2009. The NTCRA design was subject to a value engineering study and independent review in 2008. The design for Copperas Factory cleanup as part of the Remedial Action began in 2006 and was completed in 2008. The design for the remaining components of the Remedial Action cleanup activities is expected to be completed in 2014. Also in 2008, EPA installed of additional site control measures to limit the release of iron rich leachate until construction activities can be completed. EPA began the cleanup of the lead contamination at the Copperas Factories in June 2009. The lead contamination was completely contained by November 2009. The Copperas Factories cleanup work was completed in September 2010. EPA also mobilized to implement the portion of the NTCRA associated with the ARA funding in June 2009. Since June 2009, EPA has removed the waste material from the Mine Road area; installed two sediment control structures, screened and processed on-site material for use in the cover system; and completed an 1100 foot shallow groundwater interceptor trench. The relocation of waste rock pile TP-3 to TP-1 begin in Fall 2009 and was completed by September 2010. The installation of the cover system for the tailing impoundment was initiated in 2011. The cover system for 45 acre tailing impoundment was completed in 2012. Sampling data collected in 2010 through 2014 shows a 90% reduction in copper concentrations entering the West Branch of the Ompompanoosuc River. Biological monitoring has documented that the benthic community is improving downstream of the Site.

EPA continues to implement the NTCRA. The remaining activities include site restoration, wetland restoration, and the installation of the passive treatment system. EPA has completed the Remedial Design for the South Mine and South Open Cut components of the remedial action and will continue the Remedial Design underground workings components. EPA also continues to monitoring the surface water, sediment, and groundwater at the Site.

EPA also performed the first Five-Year Review for the Elizabeth Mine in 2014. The Five-Year Review confirmed that the completed actions under the Time-Critical Removal Action, Non-Time-Critical Removal Action, and Phase 1 Remedial Action (Copperas Factories) are protective of human health and the environment. For full long-term protection to be achieve, land use restrictions for the Copperas Factories and TP-3 must be completed.